Pre-auth service crash via unbounded SSH packet allocation
Published Jun 2, 2026 · Updated Jun 2, 2026
Uncontrolled resource consumption in Warmcat libwebsockets 4.5.0 through 4.5.8 allows remote attackers to crash SSH services. lws_ssh_parse_plaintext trusts the attacker-supplied msg_len field and allocates that declared packet size without an upper bound. Pre-authentication SSH connections can each reserve large amounts of memory, allowing repeated connections to exhaust the server and terminate the process.
Summary
What happened
Uncontrolled resource consumption in Warmcat libwebsockets 4.5.0 through 4.5.8 allows remote attackers to crash SSH services. lws_ssh_parse_plaintext trusts the attacker-supplied msg_len field and allocates that declared packet size without an upper bound. Pre-authentication SSH connections can each reserve large amounts of memory, allowing repeated connections to exhaust the server and terminate the process.
The record
- CVE
- CVE-2026-10650
- Published
- Jun 2, 2026
- Updated
- Jun 2, 2026
- Vendor
- libwebsockets
- Product
- libwebsockets
- Classifications
- CWE-404, CWE-400, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 2, 2026CVE publishedPublication date reported by the CVE source.
- Jun 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.5.0
- Affected versionversion=4.5.1
- Affected versionversion=4.5.2
- Affected versionversion=4.5.3
- Affected versionversion=4.5.4
- Affected versionversion=4.5.5
- Affected versionversion=4.5.6
- Affected versionversion=4.5.7
- Affected versionversion=4.5.8
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SSHD Pre-Auth Unbounded Allocation PoCproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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